1//===--- UnusedLocalNonTrivialVariableCheck.cpp - clang-tidy --------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "UnusedLocalNonTrivialVariableCheck.h"
10#include "../utils/Matchers.h"
11#include "../utils/OptionsUtils.h"
12#include "clang/AST/ASTContext.h"
13#include "clang/AST/ASTTypeTraits.h"
14#include "clang/AST/Type.h"
15#include "clang/ASTMatchers/ASTMatchFinder.h"
16#include "clang/ASTMatchers/ASTMatchers.h"
17#include "clang/ASTMatchers/ASTMatchersMacros.h"
18#include "clang/Basic/LangOptions.h"
19
20using namespace clang::ast_matchers;
21using namespace clang::tidy::matchers;
22
23namespace clang::tidy::bugprone {
24
25namespace {
26static constexpr StringRef DefaultIncludeTypeRegex =
27 "::std::.*mutex;::std::future;::std::basic_string;::std::basic_regex;"
28 "::std::basic_istringstream;::std::basic_stringstream;::std::bitset;"
29 "::std::filesystem::path";
30
31AST_MATCHER(VarDecl, isLocalVarDecl) { return Node.isLocalVarDecl(); }
32AST_MATCHER(VarDecl, isReferenced) { return Node.isReferenced(); }
33AST_MATCHER(VarDecl, explicitMarkUnused) {
34 // Implementations should not emit a warning that a name-independent
35 // declaration is used or unused.
36 LangOptions const &LangOpts = Finder->getASTContext().getLangOpts();
37 return Node.hasAttr<UnusedAttr>() ||
38 (LangOpts.CPlusPlus26 && Node.isPlaceholderVar(LangOpts));
39}
40AST_MATCHER(Type, isReferenceType) { return Node.isReferenceType(); }
41AST_MATCHER(QualType, isTrivial) {
42 return Node.isTrivialType(Context: Finder->getASTContext()) ||
43 Node.isTriviallyCopyableType(Context: Finder->getASTContext());
44}
45} // namespace
46
47UnusedLocalNonTrivialVariableCheck::UnusedLocalNonTrivialVariableCheck(
48 StringRef Name, ClangTidyContext *Context)
49 : ClangTidyCheck(Name, Context),
50 IncludeTypes(utils::options::parseStringList(
51 Option: Options.get(LocalName: "IncludeTypes", Default: DefaultIncludeTypeRegex))),
52 ExcludeTypes(
53 utils::options::parseStringList(Option: Options.get(LocalName: "ExcludeTypes", Default: ""))) {}
54
55void UnusedLocalNonTrivialVariableCheck::storeOptions(
56 ClangTidyOptions::OptionMap &Opts) {
57 Options.store(Options&: Opts, LocalName: "IncludeTypes",
58 Value: utils::options::serializeStringList(Strings: IncludeTypes));
59 Options.store(Options&: Opts, LocalName: "ExcludeTypes",
60 Value: utils::options::serializeStringList(Strings: ExcludeTypes));
61}
62
63void UnusedLocalNonTrivialVariableCheck::registerMatchers(MatchFinder *Finder) {
64 if (IncludeTypes.empty())
65 return;
66
67 Finder->addMatcher(
68 NodeMatch: varDecl(isLocalVarDecl(), unless(isReferenced()),
69 unless(isExceptionVariable()), hasLocalStorage(), isDefinition(),
70 unless(hasType(InnerMatcher: isReferenceType())), unless(hasType(InnerMatcher: isTrivial())),
71 unless(explicitMarkUnused()),
72 hasType(InnerMatcher: hasUnqualifiedDesugaredType(
73 InnerMatcher: anyOf(recordType(hasDeclaration(InnerMatcher: namedDecl(
74 matchesAnyListedName(NameList: IncludeTypes),
75 unless(matchesAnyListedName(NameList: ExcludeTypes))))),
76 templateSpecializationType(hasDeclaration(InnerMatcher: namedDecl(
77 matchesAnyListedName(NameList: IncludeTypes),
78 unless(matchesAnyListedName(NameList: ExcludeTypes)))))))))
79 .bind(ID: "var"),
80 Action: this);
81}
82
83void UnusedLocalNonTrivialVariableCheck::check(
84 const MatchFinder::MatchResult &Result) {
85 const auto *MatchedDecl = Result.Nodes.getNodeAs<VarDecl>(ID: "var");
86 diag(MatchedDecl->getLocation(), "unused local variable %0 of type %1")
87 << MatchedDecl << MatchedDecl->getType();
88}
89
90bool UnusedLocalNonTrivialVariableCheck::isLanguageVersionSupported(
91 const LangOptions &LangOpts) const {
92 return LangOpts.CPlusPlus;
93}
94
95std::optional<TraversalKind>
96UnusedLocalNonTrivialVariableCheck::getCheckTraversalKind() const {
97 return TK_IgnoreUnlessSpelledInSource;
98}
99
100} // namespace clang::tidy::bugprone
101

source code of clang-tools-extra/clang-tidy/bugprone/UnusedLocalNonTrivialVariableCheck.cpp